In refrigerant and air conditioning systems, it is common practice to employ simple O-rings to seal the various joints therein such as at the compressor, condenser, evaporator and in the line fittings as well. However, it has been proposed at least in the case of automotive air conditioning systems, that a one piece seal composed of elastomeric material such as rubber molded to a metallic or plastic retainer and commonly known as an "integral" seal be substituted for the conventional O-ring. However, tests on current state of the art integral seals have shown unsatisfactory performance with respect to Freon containment due to Freon leakage around the sealing surfaces and permeation of the Freon gas through the elastomer via defusion mechanisms.